This invention relates to a lens unit and a photographing apparatus, and relates in particular to a lens unit equipped with a zooming mechanism of a bending optical system.
In recent years, as personal computers have become more widely used, digital cameras in which images can be easily taken in to personal computers have also become widespread. In addition, it is becoming commonplace for digital cameras to be incorporated into information processing devices such as mobile computers, cellular phones, and personal digital assistants (PDAs). As digital cameras have become more widespread, there has been a desire for more compact digital cameras, and the lens unit needs to be even more compact. There is also a demand for a high magnification zoom lens and a zooming mechanism that can be used with the high magnification zoom lens is needed.
As a result, it has been proposed that in order to make the lens unit more compact, the depth direction of the digital camera is shortened without changing the total length of the photographing lens even when zooming is done, and thereby achieve compactness (Unexamined Japanese Patent Application Publication No. 2000-131610 and U.S. Pat. No. 6,850,373B2). These have a bending member on the optical path, and after the optical path is bent by about 90 degrees, an optical image is formed on the image pickup element using successive lens groups.
However, although the lens unit is definitely made more compact in the two documents described above, the variable power ratio of the photographic lens is small because zooming is performed by moving lens located on the image pickup element side from the bending member.
In order to solve this problem, a high magnification zooming lens has been proposed in which zooming is performed
by moving lens located on the image pickup element side from the bending member and lens located on the object side from the bending member (Unexamined Japanese Patent Application Publication No. 2004-102089).
However, in the zoom lens described in Unexamined Japanese Patent Application Publication No. 2004-102089, aberration is favorably corrected in high variable power, and a high performance optical system is disclosed, but a mechanism for moving the lens that are arranged in the vicinity of the bending member for zooming is not disclosed, and the object side lens projects out from the digital camera and this causes the camera to be bulky.